FTP “curve”

[RockCaCO3]

Hi Lynda,

I’ve searched the forum/googled the following question; I may be overthinking this, but I have a question about ftp.

If ftp is the power a cyclist can sustain for 1 hour, what power can that cyclist sustain for 2 hours? 3 hours? 30 minutes? I’m assuming ftp is not linear, which is why I’m trying to locate an ftp curve.

I ask, in part, because I have a race that I anticipate taking ~ 3 hours, and I’d like to identify a ballpark power I should try to maintain.

Thanks,
Cory

[Dave]

Hi Cory,

I like to think in terms of IF – intensity factor. This is calculated as normalized power over FTP. So, an IF of 1 is an FTP 100% effort. .7 is a typical L2 type of ride.

To help figure out how athletes do at different durations I’ve created something called an IF-Duration curve. This shows the IF that can be sustained for durations out to as long as their longest rides. In theory it should be at 1 right at 1 hour, above one to the left (shorter durations), and below 1 to the right (durations over an hour).

The slope of this curve is most interesting, and depends on the rider in terms of training focus and natural ability. Those with more natural ability in the shorter events will have lower sustainable IFs around 3 hours than athletes that aren’t gifted sprinters and train long durations often.

The range in my athlete data is 0.8 to 0.95. Decide where you fall on that spectrum and take a wag in that range. FYI that .95 value is an outlier, most values are closer to .88-.89. Keep in mind whatever you decide, the only real way to know is to test it!

How to use this number is another matter. I’d recommend using normalized power to pace the full event effort. IF target * FTP is the NP you’d use as your pacing goal. For example, if you chose .88 and your FTP is 300 you’d use .88*300=264W NP as your target pace.

Hope that helps!
Coach Dave

[RockCaCO3]

Dave,

That does help, thanks!

Cory

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